<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .float {
      float: left;
      text-align: center;
    }
    .main {
      width: 100%;
      height: 200px;
      background-color: #2aabd2;
    }
    .main-info {
      margin: 0 200px 0 200px;
    }
    .left {
      width: 200px;
      height: 200px;
      background-color: #4cae4c;
      margin-left: -100%;
    }
    .right {
      width: 200px;
      height: 200px;
      background-color: #b92c28;
      margin-left: -200px;
    }
  </style>
</head>
<body>
<div class="main float">
  <div class="main-info">中间内容</div>
</div>
<div class="left float">左边内容</div>
<div class="right float">右边内容</div>
</body>
</html>
